code: def compute_e0(shorefit):
      signal_0 = 0
  
      for n in range(int(shorefit.model.radial_order / 2) + 1):
          signal_0 += shorefit.shore_coeff[n] * (
              genlaguerre(n, 0.5)(0)
              * (
                  (factorial(n))
                  / (
                      2
                      * np.pi
                      * (shorefit.model.zeta**1.5)
                      * gamma(n + 1.5)
                  )
              )
              ** 0.5
          )
  
      return signal_0
  
file_path: dipy/dipy/reconst/tests/test_shore.py
imports: import warnings
  from math import factorial
  import numpy
  import numpy.testing
  from scipy.special import genlaguerre, gamma
  import pytest
  from dipy.data import get_gtab_taiwan_dsi
  from dipy.reconst.shm import descoteaux07_legacy_msg
  from dipy.reconst.shore import ShoreModel
  from dipy.sims.voxel import multi_tensor
  from dipy.utils.optpkg import optional_package
label_desc: Use image node_id 6 for calling a global function with example usage: compute_e0(shorefit) and returns: signal_0